Feed rate calculation for 3D printing

For print a 3d model I make my own toolpath for each slice layer by any coding and I want to get Feedrate. In cura engine open source software, it will automatically calculate Feedrate. Behind this calculation, what formula they used.

Cura isn't open source, but there are other slicers where you can study their source code. (eg. slic3r )

I guess it's a combination of trackwidth x layerheight, e-steps and acceleration/momentary speed. Then count in extrusion factors or mixing ratios and such...

I think feedrate is just a factor that increases or decreases the velocity of all axes including the extruder. Normally the factor is 1, and if you want to increase by 50% you use 1.5x velocity of all axes (up to the limits set by Vmax).
In addition to looking at slicer code, you can look at the marlin firmware source code, a feedrate control is implemented. I haven't looked myself but by observing what happens when the feedrate is adjusted it seems to me only the velocity is affected. Increasing acceration and/or jerk would put the printer in the danger zone of skipping steps.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

I think formula may be extrusion width multiply layer height multiply print speed.

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Mermarinc
I think formula may be extrusion width multiply layer height multiply print speed.

According the this web site that is correct.

[www.printitindustries.com]

Calculated from maximum volumetric speed in mm³ per second
Printing at 76 mm/s, with extrusion width of 0.44 mm and a 0.28mm layers height, your volumetric speed would be 76 * 0.44 * 0.28 = 9.3632 mm³/s

Edited 1 time(s). Last edit at 11/03/2018 10:23AM by Roberts_Clif.

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Computer Programmer / Electronics Technician